Worksheetsie quiz
Total questions: 86
Worksheet time: 1hrs 5mins
Name
Class
Date
1.
The product of voltage and current is called as_______
a)
EMF
b)
POWER
c)
FORCE
d)
ENERGY
2.
Name the region of operation of a transistor when it is working as a switch.
a)
Active
b)
cut off
c)
Saturation
d)
cut off & Saturation
3.
The combination of Control system,Electronics and Power system can be called as _______
a)
Linear Electronics
b)
Power Electronics
c)
Analog Electronics
d)
Digital Electronics
4.
In the below mentioned circuits which one consumes more power?
a)
Linear Amplifier
b)
Mobile charger
c)
Motor Drives
d)
Controlled rectifier
5.
The _________is an application of Power Electronics
a)
SMPS
b)
UPS
c)
Inverter
d)
All the above
6.
An ideal power diode must have
a)
low forward current carrying capacity
b)
large reverse breakdown voltage
c)
high ohmic junction resistance
d)
high reverse recovery time
7.
To make a signal diode suitable for high current & high voltage carrying applications with minimum losses, ________
a)
a lightly doped n layer is grown between the two p & n layers
b)
a heavily doped n layer is grown between the two p & n layers
c)
a lightly doped p layer is grown between the two p & n layers
d)
a heavily doped p layer is grown between the two p & n layers
8.
The V-I Characteristics of the diode lie in the
a)
1st & 2nd quadrant
b)
1st & 3rd quadrant
c)
1st & 4th quadrant
d)
Only in the 1st quadrant
9.
Which of the following is true in case of a power diode with R load?
a)
I grows almost linearly with V
b)
I decays almost linearly with V
c)
I is independent of V
d)
I initial grows than decays
10.
A diode is said to be reversed biased when the
a)
cathode is positive with respect to the anode
b)
anode is positive with respect to the cathode
c)
cathode is negative with respect to the anode
d)
both cathode & anode are negative
11.
A diode is said to be forward biased when the
a)
cathode is positive with respect to the anode
b)
anode is positive with respect to the cathode
c)
anode is negative with respect to the anode
d)
both cathode & anode are positive
12.
In case of an power diode, when diode is in OFF condition, the leakage current flows from
a)
anode to cathode
b)
cathode to anode
c)
in both the directions
d)
leakage current does not flow
13.
Which of the following diodes uses a metal-semiconductor junction?
a)
General purpose diodes
b)
Rectifier diode
c)
Schottky diode
d)
Slow recovery diode
14.
The reverse recovery time of the diode is defined as the time between the instant diode current becomes zero and the instant reverse recovery current decays to
a)
Zero
b)
10% of the reverse peak current (IRM)
c)
25% of (IRM)
d)
15% of (IRM)
15.
The softness factor for soft-recovery and fast-recovery diodes are respectively
a)
1, >1
b)
<1, 1
c)
1, 1
d)
1, <1
16.
Which following is a two terminal three layer device?
a)
MOSFET
b)
BJT
c)
POWER DIODE
d)
SCR
17.
Power diode is __________
a)
a three terminal semiconductor device
b)
a two terminal semiconductor device
c)
a four terminal semiconductor device
d)
a three terminal analog device
18.
When the p-n junction diode is forward biased, the width of the depletion region __________
a)
increases
b)
decreases
c)
remains Constant
d)
None of the above
19.
When the p-n junction diode is reversed biased, the width of the depletion region __________
a)
increases
b)
decreases
c)
remains Constant
d)
None of the above
20.
A thyristor is reverse biased. A positive gate pulse is applied. The thyristor
a)
will be turned on
b)
may or may not turn on
c)
will not turn on
d)
will turn on after sometime
21.
Why an SCR is considered to be a semi controlled device because
a)
it can be turned OFF but not ON with a gate pulse.
b)
it conducts both half cycles of an alternating wave.
c)
it can be turned ON but not OFF with a gate pulse.
d)
it can be turned ON only during one half cycle of an DC.
22.
The SCR is turned -off when the anode current falls below_____
a)
Forward current
b)
Latching current
c)
Holding current
d)
Leakage current
23.
In a SCR circuit, the angle of conduction is changed by changing______
a)
Anode voltage
b)
Positon of the Gate pulse applied.
c)
Reverse current
d)
Leakage current
24.
Which terminal does not belong to the SCR?
a)
Anode
b)
Gate
c)
Base
d)
Cathode
25.
If the cathode of an SCR is made positive with respect to the anode & no gate current is applied then
a)
all the junctions are reversed biased
b)
all the junctions are forward biased
c)
only the middle junction is forward biased
d)
only the middle junction is reversed biased
26.
For an SCR in the reverse blocking mode, (practically)
a)
leakage current does not flow
b)
leakage current flows from anode to cathode
c)
leakage current flows from cathode to anode
d)
leakage current flows from gate to anode
27.
A thyristor can be bought from the forward conduction mode to forward blocking mode by
a)
the dv/dt triggering method
b)
applying a negative gate signal
c)
applying a positive gate signal
d)
applying a reverse voltage across anode-cathode terminals
28.
The forward break over voltage is maximum when
a)
Gate current = ∞
b)
Gate current = 0
c)
Gate current = -∞
d)
It is independent of gate current
29.
The natural reversal of ac supply voltage commutates the SCR in case of
a)
forced commutation
b)
only line commutation
c)
only natural commutation
d)
both line & natural commutation
30.
Natural commutation of an SCR takes place when
a)
voltage across the device becomes infinite
b)
voltage across the device becomes positive
c)
gate current becomes zero
d)
anode current becomes zero
31.
Class E commutation is a__________
a)
line commutation technique
b)
load commutation technique
c)
forced commutation technique
d)
external-pulse commutation technique
32.
The GTO (gate turn-off thyristor) is a
a)
p-n-p-n device
b)
p-n-p device
c)
p-metal-n device
d)
p-n single junction device
33.
The GTO can be turned off
a)
by a positive gate pulse
b)
by a negative gate pulse
c)
by a negative anode-cathode voltage
d)
by removing the gate puls
34.
Latching current for the GTOs is ________ as compared to CTs (Conventional thyristors).
a)
more
b)
less
c)
constant
d)
cannot be said
35.
A GTO can be turned on by applying
a)
Positive gate signal
b)
Positive drain signal
c)
Positive source signal
d)
by a negative gate pulse
36.
Which semiconductor power device out of the following, is not a current triggering device?
a)
Triac
b)
G.T.O
c)
MOSFET
d)
SCR
37.
How many minimum thyristors make up a TRIAC
a)
0
b)
1
c)
2
d)
3
38.
The TRIAC can be represented by
a)
two SCRs in anti-parallel
b)
two SCRs in parallel
c)
two diodes in anti-parallel
d)
two diodes in parallel
39.
How many terminals does a TRIAC have?
a)
1
b)
2
c)
3
d)
4
40.
How many layers of semiconductor does a TRIAC have?
a)
1
b)
2
c)
3
d)
4
41.
IGBT possess
a)
low input impedance
b)
high input impedance
c)
high on-state resistance
d)
5 terminals
42.
The three terminals of the IGBT are
a)
base, emitter & collector
b)
gate, source & drain
c)
gate, emitter & collector
d)
base, source & drain
43.
When latch-up occurs in an IGBT
a)
Ig is no longer controllable
b)
Ic is no longer controllable
c)
the device turns off
d)
Ic increases to a very high value
44.
The approximate equivalent circuit of an IGBT consists of
a)
a BJT & a MOSFET
b)
a MOSFET & a MCT
c)
two BJTs
d)
two MOSFETs
45.
IGBT & BJT both posses ___
a)
low on-state power losses
b)
high on-state power losses
c)
low switching losses
d)
high input impedance
46.
The controlling parameter in IGBT is the
a)
IG
b)
VGE
c)
IC
d)
VCE
47.
The structure of the IGBT is a
a)
P-N-P structure connected by a MOS gate
b)
N-N-P-P structure connected by a MOS gate
c)
P-N-P-N structure connected by a MOS gate
d)
N-P-N-P structure connected by a MOS gate
48.
Which of the following device incorporates a terminal for synchronizing purposes?
a)
Diac
b)
Triac
c)
SUS
d)
SCR
49.
From the following list of devices, choose the device that only turns-on for a fixed-value of anode-cathode voltage
a)
Transistor
b)
MOSFET
c)
SUS
d)
BJT
50.
Which of the following devices can be used for isolation ?
a)
Diode
b)
Opto Coupler
c)
SCR
d)
DIAC
51.
Which of the following devices can be triggerred with light
a)
Diode
b)
LASCR
c)
SUS
d)
DIAC
52.
The total number of leads in RCT is
a)
1
b)
2
c)
3
d)
4
53.
An RCT consists of __________in parallel
a)
Reverse diode
b)
Forward diode
c)
resistor
d)
inductor
54.
The SITH (Static Induction Thyristor) is a
a)
4 terminal, self-controlled device
b)
3 terminal, self-controlled device
c)
4 terminal, un-controllable device
d)
3 terminal, un-controllable device
55.
The three terminals of MCT
a)
Anode, cathode, gate
b)
Collector, emitter, gate
c)
Drain, source, base
d)
Drain, source, gate
56.
Which of following is normally ON device
a)
SIT
b)
BJT
c)
TRIAC
d)
IGBT
57.
At present, the state-of-the-art semiconductor devices are begin manufactured using
a)
Semiconducting Diamond
b)
Gallium-Arsenide
c)
Germanium
d)
Silicon-Carbide
58.
The main component used in over voltage protection is ___________
a)
MOSFET
b)
Diode
c)
SCR
d)
Capacitor
59.
The over voltage protection circuit consists of ______components
a)
Diode,SCR,Zener,Capacitor
b)
MOSFET,BJT,IGBT
c)
MOSFET,capacitor
d)
resistor and capacitor
60.
In over voltage protection circuit , the SCR is connected in ______with load
a)
series
b)
parallel
c)
with BJT
d)
none of the above
61.
In induction heating, the heat produced is
a)
A. Directly proportional to the induced voltage and inversely proportional to the resistance
b)
A. Inversely proportional to the induced voltage and directly proportional to the resistance
c)
A. Directly proportional to the square of induced voltage and inversely proportional to the resistance
d)
A. Inversely proportional to the square of induced voltage and directly proportional to the resistance
62.
Induction heating requires_____________
a)
High Frequency AC
b)
Low Frequency DC
c)
Variable DC
d)
Constant DC
63.
The main advantage of dielectric heating is that
a)
heating occurs in the material itself.
b)
heating occurs due to high frequency.
c)
it can be used for drying the explosives.
d)
None of the above.
64.
In electrical resistance welding material of electrode should have
a)
higher electrical conductivities.
b)
higher thermal conductivities.
c)
sufficient strength to sustain high pressure at elevated temperatures
d)
all of above.
65.
A battery charge circuit consist of a SCR connected as _________
a)
controlled Rectifier
b)
Protection
c)
load
d)
none
66.
An AC circuit breaker consists of _______no. of SCR's
a)
2
b)
1
c)
3
d)
4
67.
An DC circuit breaker consists of _______no. of SCR's
a)
2
b)
1
c)
3
d)
4
68.
An RC snubber circuit is used to protect a thyristor against
a)
false triggering
b)
failure to turn on
c)
switching transients
d)
failure to commutate
69.
Name the circuit which protects from sudden rate of change of current
a)
TURN ON SNUBBER
b)
TURN OFF SNUBBER
c)
OVER VOLTAGE SNUBBER
d)
RC SNUBBER
70.
Name the circuit which protects from sudden rate of change of VOLTAGE
a)
TURN ON SNUBBER
b)
TURN OFF SNUBBER
c)
USING INDUCTOR
d)
USING RESISTOR
71.
Turn ON snubber circuit uses _____component for protection
a)
Inductor
b)
MOSFET
c)
BJT
d)
resistor
72.
Turn OFF snubber circuit uses _____component for protection
a)
Capacitor
b)
MOSFET
c)
BJT
d)
resistor
73.
di/dt protection is provided to the thryistor by
a)
connecting an inductor in parallel across the load
b)
connecting an inductor in series with the load
c)
connecting an inductor in parallel across the gate terminal
d)
connecting an inductor in series with the gate
74.
dv/dt protection is provided to the SCR by
a)
connecting a capacitor in parallel with the load
b)
connecting an inductor in series with the load
c)
connecting a capacitor & resister in parallel with the device
d)
connecting an inductor & resister in parallel with the device
75.
In controlled Rectifiers _________is used for rectification
a)
SCR
b)
Capacitor
c)
transistor
d)
none
76.
In a half-wave rectifier with RL Load, the
a)
current & voltage both are bi-directional
b)
current & voltage both are uni-directional
c)
current is always uni-directional but the voltage can be bi-directional
d)
current can be bi-directional or uni-directional but the voltage is always uni-directional
77.
The Freewheeling diode is used for ________load
a)
Inductive load
b)
diode load
c)
Transistor load
d)
resistive load
78.
In the process of diode based rectification, the alternating input voltage is converted into
a)
an uncontrolled alternating output voltage
b)
an uncontrolled direct output voltage
c)
a controlled alternating output voltage
d)
a controlled direct output voltage
79.
The single phase bridge rectifier consists of ______no.of diodes
a)
1
b)
2
c)
3
d)
4
80.
The Three phase AC voltage is________
a)
220V
b)
210V
c)
440V
d)
320V
81.
The delta connected three phase cirucit has _____no. of lines
a)
1
b)
2
c)
3
d)
4
82.
The star connected three phase cirucit has _____no. of lines
a)
1
b)
2
c)
3
d)
4
83.
What is the phase difference in a 3phase AC between each phase
a)
180°
b)
120°
c)
90°
d)
60
84.
The 3 phase half wave rectifier requires _________no. of diodes
a)
1
b)
2
c)
3
d)
4
85.
The 3 phase bridge rectifier requires _________no. of diodes
a)
4
b)
6
c)
8
d)
2
86.
The Freewheeling diode is used for ________load
a)
Inductive load
b)
diode load
c)
Transistor load
d)
resistive load
100 %
